Yeah, no REM state means he would essentially be sleep deprived. There is no point in sleeping beyond REM, that’s why we sleep is to achieve it. He wouldn’t neccasarily be dead, but he would be pretty mentally messed up. Imagine a kid who has never slept a day in his life.

Sleep deprivation actually has a much more limited effect then most people can imagine, but I don’t think Nicole would just write it off if she heard he didn’t get any REM.

Well, if his brother goes brain dead the instant he hits REM, then who’s to say his twin doesn’t have another really wild and unexplainable place he goes? Such as “the place of utter blackness and forgetting about it?”